"""Support for providing temporary directories to test functions."""
import os
import re
import sys
import tempfile
from pathlib import Path
from typing import Optional

import attr

from .pathlib import LOCK_TIMEOUT
from .pathlib import make_numbered_dir
from .pathlib import make_numbered_dir_with_cleanup
from .pathlib import rm_rf
from _pytest.compat import final
from _pytest.config import Config
from _pytest.deprecated import check_ispytest
from _pytest.fixtures import fixture
from _pytest.fixtures import FixtureRequest
from _pytest.monkeypatch import MonkeyPatch


@final
@attr.s(init=False)
class TempPathFactory:
    """Factory for temporary directories under the common base temp directory.

    The base directory can be configured using the ``--basetemp`` option.
    """

    _given_basetemp = attr.ib(type=Optional[Path])
    _trace = attr.ib()
    _basetemp = attr.ib(type=Optional[Path])

    def __init__(
        self,
        given_basetemp: Optional[Path],
        trace,
        basetemp: Optional[Path] = None,
        *,
        _ispytest: bool = False,
    ) -> None:
        check_ispytest(_ispytest)
        if given_basetemp is None:
            self._given_basetemp = None
        else:
            # Use os.path.abspath() to get absolute path instead of resolve() as it
            # does not work the same in all platforms (see #4427).
            # Path.absolute() exists, but it is not public (see https://bugs.python.org/issue25012).
            self._given_basetemp = Path(os.path.abspath(str(given_basetemp)))
        self._trace = trace
        self._basetemp = basetemp

    @classmethod
    def from_config(
        cls,
        config: Config,
        *,
        _ispytest: bool = False,
    ) -> "TempPathFactory":
        """Create a factory according to pytest configuration.

        :meta private:
        """
        check_ispytest(_ispytest)
        return cls(
            given_basetemp=config.option.basetemp,
            trace=config.trace.get("tmpdir"),
            _ispytest=True,
        )

    def _ensure_relative_to_basetemp(self, basename: str) -> str:
        basename = os.path.normpath(basename)
        if (self.getbasetemp() / basename).resolve().parent != self.getbasetemp():
            raise ValueError(f"{basename} is not a normalized and relative path")
        return basename

    def mktemp(self, basename: str, numbered: bool = True) -> Path:
        """Create a new temporary directory managed by the factory.

        :param basename:
            Directory base name, must be a relative path.

        :param numbered:
            If ``True``, ensure the directory is unique by adding a numbered
            suffix greater than any existing one: ``basename="foo-"`` and ``numbered=True``
            means that this function will create directories named ``"foo-0"``,
            ``"foo-1"``, ``"foo-2"`` and so on.

        :returns:
            The path to the new directory.
        """
        basename = self._ensure_relative_to_basetemp(basename)
        if not numbered:
            p = self.getbasetemp().joinpath(basename)
            p.mkdir(mode=0o700)
        else:
            p = make_numbered_dir(root=self.getbasetemp(), prefix=basename, mode=0o700)
            self._trace("mktemp", p)
        return p

    def getbasetemp(self) -> Path:
        """Return the base temporary directory, creating it if needed."""
        if self._basetemp is not None:
            return self._basetemp

        if self._given_basetemp is not None:
            basetemp = self._given_basetemp
            if basetemp.exists():
                rm_rf(basetemp)
            basetemp.mkdir(mode=0o700)
            basetemp = basetemp.resolve()
        else:
            from_env = os.environ.get("PYTEST_DEBUG_TEMPROOT")
            temproot = Path(from_env or tempfile.gettempdir()).resolve()
            user = get_user() or "unknown"
            # use a sub-directory in the temproot to speed-up
            # make_numbered_dir() call
            rootdir = temproot.joinpath(f"pytest-of-{user}")
            try:
                rootdir.mkdir(mode=0o700, exist_ok=True)
            except OSError:
                # getuser() likely returned illegal characters for the platform, use unknown back off mechanism
                rootdir = temproot.joinpath("pytest-of-unknown")
                rootdir.mkdir(mode=0o700, exist_ok=True)
            # Because we use exist_ok=True with a predictable name, make sure
            # we are the owners, to prevent any funny business (on unix, where
            # temproot is usually shared).
            # Also, to keep things private, fixup any world-readable temp
            # rootdir's permissions. Historically 0o755 was used, so we can't
            # just error out on this, at least for a while.
            if sys.platform != "win32":
                uid = os.getuid()
                rootdir_stat = rootdir.stat()
                # getuid shouldn't fail, but cpython defines such a case.
                # Let's hope for the best.
                if uid != -1:
                    if rootdir_stat.st_uid != uid:
                        raise OSError(
                            f"The temporary directory {rootdir} is not owned by the current user. "
                            "Fix this and try again."
                        )
                    if (rootdir_stat.st_mode & 0o077) != 0:
                        os.chmod(rootdir, rootdir_stat.st_mode & ~0o077)
            basetemp = make_numbered_dir_with_cleanup(
                prefix="pytest-",
                root=rootdir,
                keep=3,
                lock_timeout=LOCK_TIMEOUT,
                mode=0o700,
            )
        assert basetemp is not None, basetemp
        self._basetemp = basetemp
        self._trace("new basetemp", basetemp)
        return basetemp


def get_user() -> Optional[str]:
    """Return the current user name, or None if getuser() does not work
    in the current environment (see #1010)."""
    import getpass

    try:
        return getpass.getuser()
    except (ImportError, KeyError):
        return None


def pytest_configure(config: Config) -> None:
    """Create a TempPathFactory and attach it to the config object.

    This is to comply with existing plugins which expect the handler to be
    available at pytest_configure time, but ideally should be moved entirely
    to the tmp_path_factory session fixture.
    """
    mp = MonkeyPatch()
    config.add_cleanup(mp.undo)
    _tmp_path_factory = TempPathFactory.from_config(config, _ispytest=True)
    mp.setattr(config, "_tmp_path_factory", _tmp_path_factory, raising=False)


@fixture(scope="session")
def tmp_path_factory(request: FixtureRequest) -> TempPathFactory:
    """Return a :class:`pytest.TempPathFactory` instance for the test session."""
    # Set dynamically by pytest_configure() above.
    return request.config._tmp_path_factory  # type: ignore


def _mk_tmp(request: FixtureRequest, factory: TempPathFactory) -> Path:
    name = request.node.name
    name = re.sub(r"[\W]", "_", name)
    MAXVAL = 30
    name = name[:MAXVAL]
    return factory.mktemp(name, numbered=True)


@fixture
def tmp_path(request: FixtureRequest, tmp_path_factory: TempPathFactory) -> Path:
    """Return a temporary directory path object which is unique to each test
    function invocation, created as a sub directory of the base temporary
    directory.

    By default, a new base temporary directory is created each test session,
    and old bases are removed after 3 sessions, to aid in debugging. If
    ``--basetemp`` is used then it is cleared each session. See :ref:`base
    temporary directory`.

    The returned object is a :class:`pathlib.Path` object.
    """

    return _mk_tmp(request, tmp_path_factory)
